The common toilet seat assembly has been known for over a century. The installation of the toilet seat assembly has always required the installer to maneuver under the back end or flange of the toilet bowl or to reach under the flange. This type of installation has always made removal of the toilet seat assembly for cleaning a cumbersome task. The result has been that the seat assembly is usually only removed when there is a need to change it. Additionally, after remaining in place for a considerable period of time, the nuts and bolts that maintain the seat assembly in place are often badly corroded making removal very difficult, and more so when it is necessary to reach under the flange or get down beneath the flange to perform this task.
A patent to Pryor describes a seat assembly that is fastened to the rear flange of the bowl by downwardly facing screws and held within countersinks on the under side of the flange with washers and nuts. This arrangement requires the fastening of the nuts into the countersink from beneath the flange. (U.S. Pat. No. 976,395)
Another toilet bowl hinge arrangement is made of stamped metal that is secured to the bowl flange by a downwardly facing round headed carriage bolt having a square shoulder that fits into a square countersink in the top of the flange. The shank of the bolt is smooth with a threaded end portion. This bolt must be fastened in place under the flange and a nut is used that is flush with the bottom surface of the flange. (Mears, U.S. Pat. No. 1,799,309) In U.S. Pat. No. 4,820,096, Knight discloses a nut and bolt apparatus for use in securing a toilet seat assembly to the toilet bowl flange. A threaded bolt is passed downward through openings in the back of the seat assembly and the flange and is secured in place under the flange with a threaded nut having a horizontal arm. The nut is thereafter turned from below the flange until the arm contacts the lower surface of the bowl at which time it can no longer turn. The installer must then tighten the bolt from above. The upper part of the nut is conical so it may rest part way into the opening in the flange. When the bolt is tightened a part of the conical nut is drawn up into the opening for a tight fit. Though the bolt is tightened from above, the nut must still be seated and turned from beneath the flange. Newman et al., in U.S. Pat. No. 5,980,150, discloses a smooth cylindrical bolt having a linear key way near the bottom. The bolt is inserted through the holes in the seat assembly bracket and the bowl flange from above. Under the flange a spring is slipped over the lower portion of the bolt followed by a sleeve. The bolt can be given a quarter turn in the sleeve so the key way faces an axial opening wherein a threaded nipple locks the bolt in place. An installer would have to access the threaded nipple from below the flange in order to install the seat assembly or to remove it.
Watson, in U.S. Pat. No. 3,570,021, describes a toilet seat assembly that can be installed from above the flange. The seat assembly bracket has two downwardly projecting stems that fit into the stud holes in the toilet bowl flange. The stems have a flared opening at the bottom. A threaded bolt held in place with a nut is placed into each stem before the seat assembly is put in place. Once in place the bolts are tightened within the stems pulling the nuts up into the flared opening and in turn forcing the walls of the stem to flare out against the stud holes to secure the seat assembly in place. Such an assembly is also subject to rusting which will render it impossible to remove the assembly. Frequent removal and replacement can strip the inside of the stem causing fatigue which will no longer permit tightening of the nut. A seat assembly that can be easily removed and replaced is taught by Corda in U.S. Pat. No. 4,079,471. A threaded post having a smooth upper portion extending above a flat bushing is set into each hole in the bowl flange and secured with a nut from below. The bracket of the seat assembly has two smooth walled cylindrical bushings that fit over the smooth upper portions of the posts enabling the seat assembly to be taken off and replaced while the bolt remains in place. After time the connections can become loose so that the seat assembly will no longer be held securely in place. A similar arrangement is taught by Hulsebus et al. in U.S. Pat. No. 5,933,875 where a bolts are passed downward through base members and the holes in the bowl flange and are secured with nuts under the flange. Locking members that cooperate with the base members above the flange fasten the seat assembly in place. The locking members enable the seat assembly to be removed and replaced. See also U.S. Pat. No. 6,381,762 to Moser.
Another system that enables removing the seat assembly from above the flange is disclosed by Reed in U.S. Pat. No. 5,457,824. A hollow bolt threaded on its outer surface and smooth on its inner surface is placed into each hole in the flange and must be secured with a nut from below the flange. The seat assembly mounting bracket is placed over the two bolts and a hollow pin is placed into each bolt. A screw is then placed into each pin and turned so the walls of the pin are forced against the inner sides of the hollow bolt to secure the seat assembly. A similar system is disclosed in UK Patent Application GB2 167 096 A. Such systems will exhibit fatigue after the seat assembly is repeatedly removed and replaced.
Edgcumbe discloses a toilet seat hinge assembly that is affixed to the bowl flange by bolts that have smooth stems and threaded ends. The bolts are introduced upwardly into the holes in the bowl flange from below the flange and the threaded ends must be screwed into cooperating covered threaded channels in the seat assembly brackets. The openings in the underside of the brackets must be placed exactly over the holes to accept the bolts. These bolts must be introduced from the underside of the flange and tightened from the underside of the flange. There is no access to the bolts from above. (U.S. Pat. No. 1,975,570) In U.S. Pat. No. 3,254,363 Watson discloses using a threaded studs that are screwed directly into sockets on the underside of the hinge posts of the seat assembly. The studs are then lowered into the holes in the bowl flange. A soft washer must be pushed up onto each stud from below the flange followed by plastic nuts having toothed top surfaces. As the nuts are tightened on the studs from below the flange the teeth grip the soft washer and force is exerted on the stud pulling it downward for a tight fit.
Schlegel, in U.S. Pat. No. 1,559,283 teaches the use of a bolt with a square shank and a round threaded end that is inserted upward into the holes in the bowl flange from below. The flange holes are also square so the bolts cannot rotate once set in place. The threaded end passes through openings in the back of the seat assembly and are maintained in place by closed nuts having a lubricant reservoir in the top to prevent rusting. When the seat assembly is to be removed, the nuts can be taken off from above, but the bolts must be caught from below or they will fall to the floor. The fixed length of the bolts cannot accommodate variations in the thickness of the flange that may occur from one toilet bowl assembly to another.
Most of the prior art patents disclose a system whereby the seat assembly can be removed for cleaning and replaced only by gaining access to removable nuts situated under the flange where space is usually very limited and access is difficult. Even those prior art systems that enable removal of the seat assembly from above the flange require setting the main bolts with nuts that are screwed on from below. Many seat assemblies currently on the market come with two downwardly facing bolts permanently attached to the seat brackets. These bolts must be inserted downwardly into the flange openings and fastened with nuts from below the flange. The only way to remove these seat assemblies is to reach under the flange to remove the two nuts. After time the nuts and bolts often become severely corroded making the removal of the seat assembly even more difficult.
With present day requirements for sanitary provisions that were not necessary only a few years ago there is a need for a bolt arrangement to affix a toilet seat assembly to the bowl flange that enables the seat assembly to be easily removed for cleaning and where the access to the fastening bolts for the removal of the seat assembly is made from above the flange. There is a need for such a system that is compatible with existing toilet bowl fixtures.